Announcement

Collapse
No announcement yet.

Modding the Lepai T2020A+

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • Modding the Lepai T2020A+

    Finally got enough time to make this writeup.

    The Lapai Class-T T2020A+ amplifier is available on Parts Express for a measly $22.80. At 20W RMS x 2 channels, that's a lot of power for a very little money.

    However, there's a reason these are so cheap, and this thread will show you how to modify these to improve output and sound quality.

    From what I can tell, there are 2 major deficiencies with this amplifier.

    Power Supply
    First is the power supply, which cannot physically deliver the rated power, being only a 2 amp power supply at 12V. Assuming a 90% efficiency, that's only 21.6W of power when we need 40W. When playing harder bass beats, the unit's lights will dim and the unit will eventually shut down due to undervoltage. Below is a link for a more suitable power supply. I have since purchased four of these power supplies and they have all worked flawlessly.

    http://cgi.ebay.com/ws/eBayISAPI.dll...=STRK:MEWNX:IT


    Capacitors
    These are all sorts of messed up. Quality control and consistency on these amplifiers is just short of depressing. The units will arrive with a variety of capacitors, some of which even appear to be used. While they do have the same ratings, they are certainly not the same. I previously received a unit with an input capacitor that was soldered with the polarity reversed. This resulted in smoke and electrolytic goop splattered inside the amplifier when I tried to use it. As a result, I recommend replacing the capacitors. However, be mindful of the polarity.

    I have uploaded a few attachment images in this post for reference. I will refer to their filenames.

    The first 4 images titled StockAmp* are what the amp looks like when you first open it. You will notice that in these two samples, the input capacitors look differnet. One looks either used or very heavily handled. In addition, the output capacitors look different, with one having small and red, and another having medium and red capacitors. A previous sample of mine had small and blue capacitors.

    The last image is titled AmpDiagram. The capacitors are color coded for simplicity, and a link to the item on mouser.com is provided.



    In Yellow is the input capacitor. This is a 16V 3300uf 20% capacitor. I have opted to upgrade this to a 16V 5600uf Low ESR capacitor.
    http://www.mouser.com/Search/Product...67-EEU-FR1C562

    In Red are the output capacitors. These are 63V .47uf +80/-20% capacitors. They have a very loose tolerance. I believe that replacing these made the biggest difference. The replacements are 450V .47uf 5% capacitors. You will need six. One thing to note: there are 3 holes for these capacitors to be soldered through; one on one side and two other other. The stock capacitors use the inner hole. You can use the outer hole to solder the upgraded capacitor, as they are wider.
    http://www.mouser.com/Search/Product...-ECW-F2W474JAQ

    In Magenta/Pink is a film capacitor. It is a 63V .1uf capacitor. I have no idea what it does, but I replaced it anyway because its only $0.68.
    http://www.mouser.com/Search/Product...-ECW-F2W104JAQ

    In Green are a bunch of electrolytic capacitors. These are rated as follows. Disregard the two in orange for now:
    2 x 16v 100uf
    1 x 16v 470uf
    2 x 16v 220uf
    2 x 50v 1uf
    These were replaced with Nichicon Audio Grade capacitors. Just match the values on the old ones when you remove them with the new ones.
    http://www.mouser.com/Search/Product...47-UKW1H010MDD
    http://www.mouser.com/Search/Product...47-UKW1E221MPD
    http://www.mouser.com/Search/Product...47-UKW1C471MPD
    http://www.mouser.com/Search/Product...47-UKW1C101MDD

    In Orange are two 50v 1.7uf capacitors. I had initially bought two 2.2uf capacitors to replace these, but after replacing them, I had a great deal of distortion and discovered that the value needs to be kept the same, so I put the stock ones back in. Unless you can find 1.7uf capacitors to replace them, leave them alone.

    I will post pictures of the modded amps in the next post.
    Attached Files
    Last edited by XtremeRevolution; 08-11-2011, 03:58 PM.
    Modding the Lepai T-Amp

  • #2
    Re: Modding the Lepai T2020A+

    Attached are the amps with the upgraded capacitors. I used 4700uf input capacitors for these because I had them available at the time, but I recommended 5600uf input capacitors as they will also fit and have a higher capacity.

    The upgraded units have more snappy bass, can play those bass notes with more clarity, can play louder without distortion, and sound clearer and more spacious. By comparison to the upgraded amplifiers, the stock amplifiers sound like they're being played in a bathroom. Upgrading these capacitors really opens up the potential in these amplifiers.

    I have used one of these all summer long to power Dan Radick's Aurbacs (Aura NS6 + Vifa tweeter) during the outdoor parties and bonfires I've had in my back yard, with my wife constantly telling me to turn them down because she can't talk over them.
    Attached Files
    Last edited by XtremeRevolution; 08-10-2011, 10:24 PM.
    Modding the Lepai T-Amp

    Comment


    • #3
      Re: Modding the Lepai T2020A+

      Thanks dude - I just got one of these, and like it a lot, but now I'm going to have to order another one so I can mod it and compare! We are not concerned (at this time) about maximum volume, so I'll probably just do some of the easy recapping.

      I think I hear a difference - wow, it's amazing!" Ethan Winer: audio myths
      "As God is my witness I'll never be without a good pair of speakers!" Scarlett O'Hara

      High value, high quality RS150/TB28-537SH bookshelf - TARGAS NLA!
      SB13/Vifa BC25SC06 MTM DCR Galeons-SB13-MTM
      My Voxel min sub Yet-another-Voxel-build

      Tangband W6-sub

      Comment


      • #4
        Re: Modding the Lepai T2020A+

        Originally posted by donradick View Post
        Thanks dude - I just got one of these, and like it a lot, but now I'm going to have to order another one so I can mod it and compare! We are not concerned (at this time) about maximum volume, so I'll probably just do some of the easy recapping.
        Well, unless you have small and steady fingers, the 6 output caps (the ones that make the biggest difference) will be the most difficult ones to replace. I got the hang of it the 3rd time around, but you end up melting the edges of the speaker terminals and the relay before its all said and done. That is, unless you don't have to solder on both sides of the PCB for those. When I followed the traces, it appeared that you did.

        Good luck!
        Modding the Lepai T-Amp

        Comment


        • #5
          Re: Modding the Lepai T2020A+

          In the first post, last image, orange box, 2- 50v 1.7uf caps. Are those non polarized caps? It's hard to see in the photo. One more question, can you tell the value of C30 and C31 surface mount caps? Maybe changing them to a larger value would lower the low frequency roll off, if that's wanted.

          Comment


          • #6
            Re: Modding the Lepai T2020A+

            Originally posted by Dirttracker73 View Post
            In the first post, last image, orange box, 2- 50v 1.7uf caps. Are those non polarized caps? It's hard to see in the photo. One more question, can you tell the value of C30 and C31 surface mount caps? Maybe changing them to a larger value would lower the low frequency roll off, if that's wanted.
            I'd have to open one to figure it out regarding C30 and C31. Might be a while before I get to that though. The 1.7uf caps appear to be non-polar, as polar caps typically have a white stripe on one side and these do not.
            Modding the Lepai T-Amp

            Comment


            • #7
              Re: Modding the Lepai T2020A+

              Very nice post, thank you!!!

              Comment


              • #8
                Re: Modding the Lepai T2020A+

                Originally posted by XtremeRevolution View Post
                Attached are the amps with the upgraded capacitors. I used 4700uf input capacitors for these because I had them available at the time, but I recommended 5600uf input capacitors as they will also fit and have a higher capacity.

                The upgraded units have much more snappy and much louder bass, can play louder without distortion, and sound clearer and more spacious. By comparison to the upgraded amplifiers, the stock amplifiers sound like they're being played in a bathroom. Upgrading these capacitors really opens up the potential in these amplifiers.

                I have used one of these all summer long to power Dan Radick's Aurbacs (Aura NS6 + Vifa tweeter) during the outdoor parties and bonfires I've had in my back yard, with my wife constantly telling me to turn them down because she can't talk over them.
                Did you measure the out put? were they able to but out 30+ with the changed power supply?

                Comment


                • #9
                  Re: Modding the Lepai T2020A+

                  Originally posted by Pete00t View Post
                  Did you measure the out put? were they able to but out 30+ with the changed power supply?
                  I didn't actually measure the output, but the speakers were able to play distinctly louder without distortion than they were able to prior to upgrading the power supply. I'm fairly certain the units can now deliver their rated 20W per channel. They had absolutely no problems driving the Aurbacs at very high volumes. My little brother is using one to drive a pair of Polk Monitor 40s to the point where the neighbors complain. These modifications do make this a completely different amplifier.
                  Modding the Lepai T-Amp

                  Comment


                  • #10
                    Re: Modding the Lepai T2020A+

                    Originally posted by XtremeRevolution View Post
                    Finally got enough time to make this writeup.

                    The last image is titled AmpDiagram. The capacitors are color coded for simplicity, and a link to the item on mouser.com is provided.

                    I will post pictures of the modded amps in the next post.
                    thank you, thank you. This is great the AmpDiagram make it clear which ones need to be replaced.

                    I will study these in detail and will try it on mine.

                    Comment


                    • #11
                      Re: Modding the Lepai T2020A+

                      how can I disable the tone control unit?, find on mine sounds much clearer bypassing the tone control.

                      Comment


                      • #12
                        Re: Modding the Lepai T2020A+

                        Originally posted by gychang View Post
                        how can I disable the tone control unit?, find on mine sounds much clearer bypassing the tone control.
                        No idea. I'd start by upgrading these parts to see if you like how it sounds better that way. Perhaps someone with more amplifier knowledge than I have can chime in to answer that question.
                        Modding the Lepai T-Amp

                        Comment


                        • #13
                          Re: Modding the Lepai T2020A+

                          How much was everything together? I'm wondering how it stacks up against the 99-5 dollar dayton amp.

                          Comment


                          • #14
                            Re: Modding the Lepai T2020A+

                            Originally posted by mintos View Post
                            How much was everything together? I'm wondering how it stacks up against the 99-5 dollar dayton amp.
                            $22.80 for the amp + ? Shipping
                            $9.13 for the capacitors + $6.95 shipping
                            $10.25 for the power supply

                            Total: $49.13.

                            Total for only mods: $26.33

                            I can't comment how it would stack up against the Dayton amps because I haven't actually taken them apart to see the quality of the components used.
                            Modding the Lepai T-Amp

                            Comment


                            • #15
                              Re: Modding the Lepai T2020A+

                              Originally posted by gychang View Post
                              how can I disable the tone control unit?, find on mine sounds much clearer bypassing the tone control.
                              There is a switch on the front of mine that allows me to turn off the tone controls.

                              Comment

                              Working...
                              X